How hot is the wire: Optical, electrical, and combined methods to determine filament temperature

Arnoud J. Onnink* (Corresponding Author), Jurriaan Schmitz, Alexey Y. Kovalgin

*Corresponding author for this work

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    Abstract

    The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.

    Original languageEnglish
    Pages (from-to)22-32
    Number of pages11
    JournalThin solid films
    Volume674
    DOIs
    Publication statusPublished - 31 Mar 2019

    Fingerprint

    Heat radiation
    filaments
    wire
    Wire
    optics
    Pyrometry
    Acoustic impedance
    thermal radiation
    Chemical vapor deposition
    Wavelength
    Temperature
    temperature
    radiation spectra
    electrical resistance
    emittance
    temperature measurement
    transmittance
    vapor deposition
    electrical resistivity
    wavelengths

    Keywords

    • Emittance
    • Filament temperature
    • Hot-wire assisted chemical vapor deposition
    • Planck's law
    • Pyrometry
    • Radiation thermometry
    • Resistance thermometry
    • Resistivity

    Cite this

    @article{98530ec145d94d8cb9696e45c0068770,
    title = "How hot is the wire: Optical, electrical, and combined methods to determine filament temperature",
    abstract = "The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.",
    keywords = "Emittance, Filament temperature, Hot-wire assisted chemical vapor deposition, Planck's law, Pyrometry, Radiation thermometry, Resistance thermometry, Resistivity",
    author = "Onnink, {Arnoud J.} and Jurriaan Schmitz and Kovalgin, {Alexey Y.}",
    year = "2019",
    month = "3",
    day = "31",
    doi = "10.1016/j.tsf.2019.02.003",
    language = "English",
    volume = "674",
    pages = "22--32",
    journal = "Thin solid films",
    issn = "0040-6090",
    publisher = "Elsevier",

    }

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    T2 - Optical, electrical, and combined methods to determine filament temperature

    AU - Onnink, Arnoud J.

    AU - Schmitz, Jurriaan

    AU - Kovalgin, Alexey Y.

    PY - 2019/3/31

    Y1 - 2019/3/31

    N2 - The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.

    AB - The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.

    KW - Emittance

    KW - Filament temperature

    KW - Hot-wire assisted chemical vapor deposition

    KW - Planck's law

    KW - Pyrometry

    KW - Radiation thermometry

    KW - Resistance thermometry

    KW - Resistivity

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